Deck over Pavers or Bare Earth

[srohara]

I was wondering if you could please help me, I am currently building a timber deck, my issue is that my bearers will have a minimum clearance of 80mm and a maximum clearance of 400mm. I am joist hanging my joists to limit my height. I am using hardwood F11 joists. I am trying to prevent wood rot so i want to know if it would be better to deck over the existing pavers or remove them and deck over bare earth. If i decide to remove the pavers i have an extra 60mm or clearance. Does bare earth or pavers retain more moisture. I can not excavate as i have a footing for a retaining wall that is only 450mm deep at the end with the lowest clearance. Please help

[brynk]

gday srohara

since you are in newcastle & therefore likely to receive high levels of rain every now & then (:wink:) may i suggest you leave the pavers in. this will prevent the growth of weeds & more weeds which will over time become a maintenance issue themselves.

yes the lesser clearance will be slightly less capable of air-circulation - and the masonry pavers will act as a barrier to moisture drainage, but they do have a certain capacity to soak up any water that does not run off. not as good as earth - not sure how wide your deck is but (400 - 80 =) 320 fall is significant even over 10 metres (1 in 60 rings a bell for a sewer line - that is 166mm fall over 10m).

in this situation the pavers will facilitate faster run-off because there will be no plant growth to trap the water as it flows away (that amount which makes its way under your deck, anyway). if your pavers extend out past the edge of your deck you can leave it at that; if not you can dig a trench along the edge of your pavers that drains away from the deck, then fill this trench with gravel/blue metal/quartz/ag. pipe - you could put some plastic or weed-matting in the bottom under the rocks for longevity. this will ensure any runoff from the pavers makes its way out from under the deck & into your veggie patch or the rose bushes!

r's brynk

just reading back over my post they make a felt-like sock that goes over the aggy pipe (this is a black plastic pipe with small holes in it). you can then lay your pipe directly in the trench & backfill with rocks or sand. the 'non-woven geotextile fabric sock' will prevent weeds & roots from working their way into the drainage pipe... http://www.landplan.com.au/Other_products.htm

[srohara]

My measurements for the deck are 6.6m x 4.5 - 5m the deck is not square due to retaining wall and boundary. the fall is about 30-40cm over the 4.5m. So you would leave the pavers down? i am going to paint the bearers and joists with Masons Cellavit Green & Masons Protect timber.